1. Field of the Invention
The present invention relates to board-to-board connectors.
2. Description of the Related Art
Conventionally, board-to-board connectors may be used to electrically connect two parallel circuit boards together. Such board-to-board connectors are configured as a mating pair of connectors each of which are attached to and project from mutually facing surfaces of two circuit boards.
FIG. 6 is a cross section of one such conventional board-to-board connector. Reference numeral 301 denotes a first connector that is mounted on a first circuit board (not shown). The first connector 301 is mated and connected with a second connector (not shown) that is mounted on a second circuit board (not shown), whereby the conductive circuits on the first and second circuit boards are electrically connected to each other. The first connector 301 includes a plurality of terminals 302 that engage counterpart terminals of the second connector.
Each of the terminals 302 has a retention portion 308 secured to an inner surface of the housing of the first connector 301 and an intermediate portion 303 connected to the retention portion 308 and extending along an outer surface of the housing. The retention portion 308 and the intermediate portion 303 engage a portion of the housing, whereby each terminal 302 is held within the first connector 301. A retention barb 309 is formed on the retention portion 308. The retention barb 309 bites or skives into the housing which increases the force holding the terminal 302 within the housing. A tail portion 304 of the terminal 302 is soldered to a corresponding conductive circuit on the surface of the first circuit board.
A contact beam 305 is connected to the retention portion 308, and extends in a direction away from the intermediate portion 303. The contact beam 305 has a generally L-shape, and includes a contact projection 306 formed at its end. When the first connector 301 is mated with the second connector (not shown), the counterpart terminals of the second connector enter recess portions 307 of the first connector 301 and the contact projection 306 of each first terminal comes into contact with a contact portion of the corresponding counterpart terminal of each second connector, whereby the conductive circuits of the first and second circuit boards are electrically connected.
In the conventional board-to-board connector pair, each terminal 302 is fixed to the housing of the first connector 301 by means of the retention portion 308 and the intermediate portion 303. Since the retention portion, from which the contact projection 306 extends, bites or skives into the housing, and the depth of the skiving cannot be easily controlled, the location of the contact projection 306 with respect to the housing may not be located consistently resulting in the first connector having relatively poor dimensional accuracy. More specifically, the inwardly facing surface of recess 307 is used as a reference surface or datum and the contact beam 305 and contact projection 306 are positioned relative thereto. However, since the retention barb skives into the housing along the inwardly facing surface of recess 307 and such skiving may not be consistent, the positioning of barb 308 and thus contact beam 305 and contact projection 306 may not be consistent within the housing. Thus, even if the dimensional accuracy of the contact beam 305 of the terminal 302 were high, the position of the contact beam 305 and the contact projection 306 in relation to the housing is difficult to maintain, which may result in difficulty in properly mating the first connector 301 with the second connector.
Furthermore, when unmating the second connector from the first connector 301, an upward force acts on the contact projection 306. Since this upward force creates a rotational moment on the contact beam 305, it places a force on the retention portion 308 and the retention barb 309 which may separate the terminal from the inwardly facing surface of the corresponding recess portion 307 of the housing and cause the retention barb 309 and the terminal 302 to loosen relative to the housing.